(a) Field of the Invention
The present invention relates to a plasma display panel (PDP), and, more particularly, to an apparatus and method to drive a PDP.
(b) Description of the Related Art
Recently, flat panel displays, such as liquid crystal displays (LCDs), field emission displays (FEDs) and PDPs, have been actively developed. The PDPs are advantageous over the other flat panel displays in regard to their high luminance, high luminous efficiency and wide viewing angle. Accordingly, the PDPs are being highlighted as a substitute for conventional cathode ray tubes (CRTs) for large-screen displays of more than 40 inches.
The PDPs are flat panel displays that use plasma generated by gas discharge to display characters or images. The PDPs include, according to their size, more than several tens to millions of pixels arranged in the form of a matrix. These PDPs are classified into a direct current (DC) type and an alternating current (AC) type according to patterns of waveforms of driving voltages applied thereto and discharge cell structures thereof.
The DC PDP has electrodes exposed to a discharge space, thereby causing current to directly flow through the discharge space during application of a voltage to the DC PDP. In this connection, the DC PDP has a disadvantage in that it requires a resistor for limiting the current. On the other hand, the AC PDP has electrodes covered with a dielectric layer that naturally forms a capacitance component to limit the current and protects the electrodes from the impact of ions during a discharge. As a result, the AC PDP is superior over the DC PDP in regard to a long lifetime.
Such an AC PDP includes scan electrodes and sustain electrodes formed on one main surface of the PDP and arranged in parallel, and address electrodes formed on the other main surface of the PDP and extending in a direction orthogonal to the scan electrodes and sustain electrodes. The sustain electrodes correspond to respective scan electrodes, and are coupled in common.
FIG. 1 is a perspective view illustrating part of an AC PDP. Scan electrodes 4 and sustain electrodes 5 covered with dielectric layer 2 and protective layer 3 are arranged in pairs in parallel on first glass substrate 1. A plurality of address electrodes 8 covered with insulation layer 7 are arranged on second glass substrate 6. Partition walls 9 are formed in parallel with address electrodes 8 on insulation layer 7 such that each partition wall 9 is interposed between adjacent address electrodes 8. Fluorescent material 10 is coated on the surface of insulation layer 7 and on both sides of each partition wall 9. First and second glass substrates 1, 6 are arranged to face each other while defining discharge space 11 therebetween so that address electrodes 8 are orthogonal to scan electrodes 4 and sustain electrodes 5. In the discharge space, discharge cell 12 is formed at an intersection between each address electrode 8 and each pair of scan electrodes 4 and sustain electrodes 5.
FIG. 2 shows an arrangement of the electrodes in the PDP. The electrodes of the PDP are arranged in the form of an m x n matrix. m address electrodes A1 to Am are arranged in a column direction. n scan electrodes Y1 to Yn and n sustain electrodes X1 to Xn are alternately arranged in a row direction. Hereinafter, the scan electrodes are referred to as “Y-electrodes”, and the sustain electrodes are referred to as “X-electrodes”.
There are various methods to display a frame by discharging cells of a PDP, such as the subfield method and the line erase scanning method. In the subfield method, one frame to be displayed in accordance with a cell discharge is divided into a plurality of sub-frames. The sub-frames are overlapped under the control of drivers for sustain electrodes and address electrodes to realize the display of one frame.
FIG. 3 illustrates driving waveforms of a conventional subfield method. As In the conventional subfield method, an address operation (write period) and a sustained discharge operation are carried out for every subfield wherein the electrodes are driven such that they are divided into a plurality of groups. However, when a number of sustain pulses are concentratedly applied to a particular electrode group in the above-mentioned PDP driving method, elements to drive the electrode group may be overloaded, thereby generating a large amount of heat. For this reason, the elements may be damaged.